Physiological Costs of Winter Warming

​Winters are getting warmer. This trend has been particularly pronounced in northeastern North America, where not only is the average winter temperature increasing but also the frequency of extremely warm days. For example, on December 24, 2015, Burlington, Vermont set a record for the daytime high temperature, reaching a balmy 20°C!

These warmer than average winters pose a potential challenge to organisms that spend the winter in a state of dormancy, such as hibernation or diapause. This is because increases in temperature may cause physiological stress that compromises the ability for these organisms to survive through the winter, when snow and ice storms threaten to freeze them to death and when they have to survive on their stored energy reserves because there is no food for them to eat.

Emily Mikucki is a PhD candidate in the Lockwood Lab who is investigating the effects of winter warming on cabbage white butterflies (Pieris rapae). Emily's exciting work has found that winter warming causes significant costs to cold tolerance and the energetic status of these animals. Overall, Emily's work suggests that future trends in winter warming may threaten northern populations of this species and even induce evolutionary adaptive responses among populations in Northeastern North America and elsewhere.